diff --git a/app/src/main/res/raw/initial_experiments.json b/app/src/main/res/raw/initial_experiments.json
index 8543827c6..9369f46a4 100644
--- a/app/src/main/res/raw/initial_experiments.json
+++ b/app/src/main/res/raw/initial_experiments.json
@@ -128,6 +128,99 @@
       "locales": null,
       "publishedDate": "2024-01-25T17:36:03.153458Z"
     },
+    {
+      "schemaVersion": "1.12.0",
+      "slug": "android-long-term-holdback-validation-first-run-sub-experiment",
+      "id": "android-long-term-holdback-validation-first-run-sub-experiment",
+      "arguments": {},
+      "application": "org.mozilla.firefox_beta",
+      "appName": "fenix",
+      "appId": "org.mozilla.firefox_beta",
+      "channel": "beta",
+      "userFacingName": "Android Long-term Holdback Validation - First-run Sub-Experiment",
+      "userFacingDescription": "This is an internal test of new experiment tooling",
+      "isEnrollmentPaused": false,
+      "isRollout": false,
+      "bucketConfig": {
+        "randomizationUnit": "nimbus_id",
+        "namespace": "fenix-nimbus-is-ready-beta-1",
+        "start": 0,
+        "count": 10000,
+        "total": 10000
+      },
+      "featureIds": [
+        "nimbus-is-ready"
+      ],
+      "probeSets": [],
+      "outcomes": [],
+      "branches": [
+        {
+          "slug": "control",
+          "ratio": 1,
+          "feature": {
+            "featureId": "this-is-included-for-mobile-pre-96-support",
+            "enabled": false,
+            "value": {}
+          },
+          "features": [
+            {
+              "featureId": "nimbus-is-ready",
+              "enabled": true,
+              "value": {
+                "event-count": 2
+              }
+            }
+          ]
+        },
+        {
+          "slug": "treatment-a",
+          "ratio": 1,
+          "feature": {
+            "featureId": "this-is-included-for-mobile-pre-96-support",
+            "enabled": false,
+            "value": {}
+          },
+          "features": [
+            {
+              "featureId": "nimbus-is-ready",
+              "enabled": true,
+              "value": {
+                "event-count": 5
+              }
+            }
+          ]
+        },
+        {
+          "slug": "treatment-b",
+          "ratio": 1,
+          "feature": {
+            "featureId": "this-is-included-for-mobile-pre-96-support",
+            "enabled": false,
+            "value": {}
+          },
+          "features": [
+            {
+              "featureId": "nimbus-is-ready",
+              "enabled": true,
+              "value": {
+                "event-count": 10
+              }
+            }
+          ]
+        }
+      ],
+      "targeting": "((is_already_enrolled) || ((isFirstRun == 'true') && (app_version|versionCompare('123.!') >= 0) && (enrollments_map['android-long-term-holdback-validation'] == 'delivery')))",
+      "startDate": "2024-02-01",
+      "enrollmentEndDate": null,
+      "endDate": null,
+      "proposedDuration": 28,
+      "proposedEnrollment": 7,
+      "referenceBranch": "control",
+      "featureValidationOptOut": false,
+      "localizations": null,
+      "locales": null,
+      "publishedDate": "2024-02-01T19:06:38.368231Z"
+    },
     {
       "schemaVersion": "1.12.0",
       "slug": "beta-fx-122-android-set-to-default-notifications-timing-experiment",